PS 3: Blood Vessels, Blood Clotting, and Cardiovascular Diseases

arteries

____ carry blood away from the heart

simple squamous epithelium/endothelium

What is the inner layer of an artery made of?

smooth muscle and elastic connective tissue

What is the middle layer of an artery made of?

elastic and collagen fibers

What is the outer layer of an artery made of?

middle layer

What gives the artery elasticity and contractility?

elastic recoil of arteries forces blood forward

What happens when the ventricles relax?

sympathetic branch of ANS

What is the smooth muscle of the artery innervated by?

smooth muscle

What is responsible for arterial contractility?

vasoconstriction

Sympathetic stimulation causes smooth muscle contraction leading to ____ and decreased flow through the vessel.

vasodilation

A decrease in sympathetic stimulation and smooth muscle relaxation results in ____

arteriole

What is the small artery that delivers blood to capillaries?

similar walls

How are arterioles similar to arteries?

consist of a layer of endothelium surrounded by smooth muscle cells

How are arterioles similar to capillaries?

capillaries

Are arterioles more similar to capillaries or arteries?

vasoconstriction; vasodilation

The smooth muscle of arterioles, like arteries, is subject to ____ and ____

capillaries

____ are microscopic vessels connecting arterioles to venules, and which permit the exchange of nutrients and wastes between blood and tissue cells

single layer of endothelial cells

What are capillaries composed of?

due to large number, allows for small diffusion distances, slow blood flow, and facilitates exchange

Why do capillaries have large surface area?

venules

____ are small veins formed by joining of several capillaries

thin walls near capillaries

How do large venules progress to structure like veins?

veins

____ have a similar structure to arteries but outer layer is thicker, middle layer is thinner, and endothelial layer is thin and folds inwards forming valves

blood reservoir

Veins, being highly distensible, act as a ____ ____, which can accommodate variable volumes of blood

blood pressure

____ ____ represents the pressure exerted by blood on the wall of a blood vessel

arterial pressure

Blood pressure, clinically, refers to ____ ____, which fluctuates in relation to ventricular systole and diastole

ejection of blood from the left ventricle

The highest pressure (systolic) corresponds to _

prior to the next ventricular ejection phase

Arterial pressure falls to its lowest point (diastole) _

sphygmomanometer

Arterial blood pressure is measured indirectly using a ____.

an inflatable compression bag enclosed in a cuff and connected to a pressure gauge

A sphygmomanometer consists of _

brachial

The cuff of a sphygmomanometer covers the ____ artery.

200; no blood flow

The cuff of a sphygmomanometer is inflated so that systolic BP reaches ____ mmHg. Why?

turbulent

When air is released from the cuff of a sphymomanometer, the flow down the brachial artery is described as ____

Kortokoff’s sounds

The intermittent sounds using a stethoscope during BP measurements are called ____.

stethoscope

What instrument allows you to hear blood flow during BP measurements?

arterioles

____ are the major resistance vessels and there is a marked drop in mean pressure as blood flows through them

nonpulsatile

The systolic-to-diastolic swings in pressure convert to a ____ pressure as blood flows through the arterioles

baroreceptor reflex; carotid sinus; carotid sinus; vasomotor center

Fast, neurally medicated ____ ____ is the increase in arterial pressure that stretches the walls of the ____ ____ (located in the neck). This increases firing of the ____ ____ nerve which carries information to the ____ ____ in the brainstem (set point is about 100 mmHg).

increased parasympathetic (vagal) outflow to the heart; decreased sympathetic outflow to the heart and Blood vessels

If mean arterial pressure is greater than 100 mmHg set point, there is ____ (decreasing heart rate) and ____ (decreased vasoconstriction of arterioles.

slow; hormonal

The mechanism that regulates blood volume is ____ and ____.

hemostasis

____ prevents blood loss from small damaged blood vessels

vasoconstriction, platelet plug formation, blood clot formation

What are the three processes that begin immediately after injury?

megakaryocytes

Platelets are formed from ____

formation on prothrombinase (prothrombin activator)

First step of blood clotting

conversion of prothrombin into thrombin by prothrombinase

Second step of blood clotting

conversion of fibrinogen to fibrin by thrombin

Third step in blood clotting

forms a mesh like network of insoluble protein that traps RBC, leukocytes, platelets, and serum at sites of vascular damage, forming a blood clot

What does fibrin do?

plasma protein formed by liver

What is prothrombin?

proteolytic enzyme

What is thrombin?

soluble plasma protein formed by liver

What is fibrinogen?

tissue factor; thromboplastin

In the extrinsic coagulation pathway, the formation of prothrombinase is initiated by ____ ____ (____), a factor extrinsic to blood

thromboplastin

____ is released from damaged tissues, and in several reaction requiring calcium ions and other coagulation factors, stage 1 is completed.

extrinsic coagulation pathway

The ____ ____ ____ initiates clotting of blood that has escaped into tissues.

surface of endothelial cells

In the intrinsic coagulation pathway, the formation of prothrombinase occurs on the ____ lining blood vessels.

intrinsic coagulation pathway

When blood comes into contact with damaged endothelial cells, the ____ is initiated.

intrinsic; extrinsic

The ____ coagulation pathway requires more steps than the ____ coagulation pathway and takes longer (several minutes).

clot retraction

Once a clot is formed, contraction of the platelets within the clot shrinks the fibrin network, pulling the edges of the damages vessel closer together in a process called ____ ____.

plasmin

The blood clot is slowly dissolved by a fibrinolytic enzyme called ____

calcium; vitamin K

____ and ____ are necessary for clot formation.

vitamin K

____ is required for the synthesis of prothrombin and certain coagulation factors.

thromboembolism

____ is when a clot may occasionally form in intact vessels

thrombus; thrombosis

A clot which stays in the place where it is formed is called a ____ in a condition called ____.

embolus; embolism

If part of a blood clot dislodges and circulates through the blood stream, the dislodged part is called a(n) ____ and the condition is called a(n) ____

atherosclerosis

____ is the process by which fatty substances are deposited in the walls of medium and large arteries and together with smooth muscle fibers of the arterial wall form a plaque obstructing blood flow.

atherosclerotic plaque

____ is a mass made of fatty substances in walls of the medium and large arteries that obstruct blood flow

A procedure to bypass a blocked section of coronary artery to deliver oxygen to the heart by connecting a blood vessel to the aorta and to the coronary artery below the blockage

What is heart bypass surgery?